• Advances in concrete construction
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• v.16 no.2
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• pp.79-89
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• 2023

The occurrence of unexpected horizontal offset in the instrument or target will result in accumulated horizontal deviation in segment alignment with traditional short-line match method. A geometry control method, the four-point method, is developed for precast segmental bridges to avoid the influences of unexpected horizontal offset. The concept of the four-point method is elucidated. Furthermore, the detailed instruments and instructions are introduced. Finally, the four-point method is validated through a practical engineering application. According to the survey data, after short-line match precast construction, the vertical deviations on both sides vary between -5 mm and 5 mm in almost all segments, and the horizontal deviations vary between -4 mm and 4 mm in all segments. Without on-site adjustment, the maximum vertical and horizontal closure gaps are 12.3 and 26.1 mm, respectively. The four-point method is suggested to alleviate the issues associated with relatively poor soil conditions in casting yard.

• Korean Journal of Remote Sensing
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• v.40 no.3
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• pp.307-316
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• 2024

On January 1, 2024, an earthquake with a moment magnitude of 7.5 occurred on the Noto Peninsula in Japan. The earthquake caused significant surface displacement on the Noto Peninsula. The surface displacement is measured by global navigation satellite system (GNSS) base stations, but there are limitations in obtaining information in areas where base stations do not exist. Therefore, in this study, we aim to determine the horizontal land surface displacement across the Noto Peninsula using offset tracking, which can detect rapidly occurring displacement. As a result of analyzing the Noto Peninsula using the offset tracking technique, it was found that more horizontal surface displacement occurred in the northwest region than in the northeast region of the Noto Peninsula, where the epicenter was located, and the surface displacement value reached a maximum of 2.9 m. The results of this study can be used to calculate surface displacement values in areas where surface displacement data are not available through ground GNSS base stations.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.111-122
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• 2020

In most cases in urban areas, construction of divergence tunnel should take into account proximity to existing tunnel in operation. This inevitably leads to deformation of adjacent structures and surrounding ground. Preceding researches mainly dealt with reinforcing of the diverging section for the stability including the pillar. This has limitations in investigating the interactive effects between existing structures and surrounding ground due to the excavation of the divergence tunnel. In this study, the complex interactive behavior of pile, the operating tunnel, and the surrounding ground according to horizontal offsets between the two adjacent tunnels was quantitatively analyzed based on conditions diverged from operating tunnel in urban areas. The effects on ground structures confirmed by analyzing the ground surface settlements, pile settlements, and the axial forces of the pile. The axial forces of lining in operating tunnel investigated to estimate their impact on existing tunnel. In addition, in order to identify the deformation of the surrounding ground, the close range photogrammetry applied to the laboratory model test for confirming the underground displacements. Two-dimensional finite element numerical analysis was also performed and compared with the results. It identified that the impact of excavating a divergence tunnel decreased as the horizontal offset increased. In particular, when the horizontal offset was larger than 1.0D (D is the diameter of operating tunnel), the impact on existing structures further reduced and the deformation of surrounding ground was concentrated at the top of the divergence tunnel.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.4
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• pp.562-569
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• 2001

This paper presents the optimum design method for T-shaped microstrip-line-fed slot antennas on various substrates. Since the impedance bandwidth of the antenna depends highly on the vertical offset position and the length of horizontal strip conductor, we derived the formulas regarding these design parameters to get the maximum bandwidth. The formulas can compute the offset position and the length of horizontal strip conductor for any given substrate parameters. We compared the results obtained by using these design formulas and the one obtained by the simulation for each slot width, and it showed very good agreement.

• Journal of Electrical Engineering and information Science
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• v.2 no.3
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• pp.132-138
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• 1997

Electrical characteristics of split-gate flash EEPROM with triple polysilicon is investigated in terms of effects of floating gate and offset gate. In order to search for t the effects of offset gate on programming characteristics, threshold voltage and drain current are studied with variation of control gate voltage. The programming process is believed to depend on vertical and horizontal electric field as well as offset gate length. The erase and program threshold voltage are found to be almost constant with variation of control gate voltage above 12V, while endurance test indicates degradation of program threshold voltage. With increase of offset gate length, program threshold voltage becomes smaller and the drain source voltage just after program under constant control gate voltage becomes higher.

• Economic and Environmental Geology
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• v.32 no.5
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• pp.495-502
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• 1999

Common-mid-point (CMP) seismic data on a dipping layer have have a stacking different from a horizontal layer velocity and the reflection points on data are dispersed to many positions. Therefore, the CMP data are not stacked well by the conventional stacking method using the horizontal layer velocity. The CMP gather can ideally stacked by applying dip-moveout(DMO) processing. Hence, modern seismic processing indludes DMO as an essential routine step. DMO processing techniques are broadly categorized by two, Fourier transform and integral methods, each of which has many different computational schemes. In this study, the dip-decomposition technique of the Fourier transform method is used to test the DMO effect on the synthetic scismic data generated for dipping structures. Each of constnat offset sections NMO corrected by using the layer velocity of the model and DMO processed. The resulting zero-offset sections for many offsets are stacked. The stacked sections with DMO processing show the structural boundaries of the models much better than those without DMO processing.

• Journal of Welding and Joining
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• v.15 no.1
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• pp.66-80
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• 1997

This paper describes a newly developed arc-sensing algorithm of seam-tracking for FCA W (flux-cored arc welding) horizontal fillet welding. In this algorithm, arc current and the Weighted-Are-Current (WAC) are used to adjust the position of a weld torch in directions of bead throat and weaving, respectively. The WAC, which is newly devised in this study, means that arc current in the vicinity of weaving end is more emphasized than that in the center of weaving. The reason of this is because there usually exists much noise in the center of weaving due to abrupt change of arc length in case some empty gaps exist in a fillet joint Variance analysis was performed in order to check the effect of weld parameters on arc current and the WAC. As a result, the relationships between tip-to-workpiece distance and arc current, and between weaving offset and the WAC were established.To check "the validity of the algorithm, seam-tracking experiments were performed ;mder various welding condition. The result of experiments showed a satisfactory tracking performance in the presence of empty gaps in a horizontal fillet joint.et joint.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.5
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• pp.685-703
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• 2017

Recently, as the number of high-rise building and earthquake occurrence are increasing, it is more important to consider horizontal load such as wind and seismic loads, earth pressure, for the pile foundation. Also, development of underground space in urban areas is more demanded to meet various problem induced by growing population. Many studies on pile subjected to horizontal load have been conducted by many researchers. However, research regarding interactive behavior on pile subjected to horizontal load with tunnel are rare, so far. In this study, therefore, study on the behaviors of ground and horizontal and vertical loads applied to single pile was carried out using laboratory model test and numerical analysis. The pile axial force and ground deformation were investigated according to offset between pile and tunnel (0.0D, 1.0D, 2.0D: D = tunnel diameter). At the same time, close range photogrammetry was used to measure displacement of underground due to tunnelling during laboratory model test. The results from numerical analysis were compared to that from laboratory model test.

• Korean Management Science Review
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• v.26 no.3
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• pp.67-78
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• 2009

In this paper, I analyze the mobile broadband services market characterized by vertical and horizontal differentiation. Vertical differentiation as service quality differentiation is based on the transmission speed of mobile internet service and horizontal differentiation as spatial differentiation is based on the service coverage. Theoretical explanations for the competitive price policy have been developed in the game context of WiBro which represent the high quality within the limited service coverage and HSDPA which represent relatively low quality with nation-wide service. When the WiBro has a mobile broadband service quality advantage and the difference in quality is sufficiently low, the price of WiBro with limited service coverage is relatively lower than that of HSDPA. This occurs because the advantage of WiBro's vertical service differentiation is offset by the disadvantage of horizontal differentiation. The difference in the quality of mobile internet service, however, is not too high, the price of WiBro is relatively higher than that of HSDPA. Moreover, when the service quality of WiBro is sufficiently high, the low quality HSDPA service faces no demand.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1832-1835
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• 1997

Off-line programming systems are widely spread in assembly lines of minute electronic products to huge offshore structures. Any OLP system has to be calibrated before the on-line robot tasks are performed because there are inherent differences between the CAD model on OLP and the real robot workspace. This paper uses simple geometric expressions to propose a calibration method applicable to an OLP for SCARA robots. A positioning task on the two-dimensional horizontal surface was used in the error analysis of a SCARA robot and the anaysis shows that the inaccuracy results from the two error sources non-zero offset angles of two rotational joints at the zero return and differences in link lengths. Pen marks on a sheet of plotting paper are used to determine the accurate data on the joint centers and link dimensions. The calculated offset angles and link lengths are fed back to the OLP for the calibration of the CAD model of the robot and task environments.